In a medium bowl, combine flour and brown sugar. Cut in butter with a pastry blender until mixture is crumbly. Press evenly into a 13 by 9 by 2-inch baking pan lined with heavy-duty aluminum foil. Bake 15 minutes or until lightly browned.

In a large bowl, beat cream cheese with 1/2 cup sugar in an electric mixer at medium speed until smooth. Then add eggs, 1 at a time, and vanilla. Stir to combine. Pour over warm crust.